'''
Created on 2011-5-22

@author: tie
'''
#f(0)=0,f(1)=1
#f(n)=f(n-1)+f(n-2)

def fibonacci(n):
    if(n==0):
        return 0
    elif(n==1):
        return 1
    else:
        return fibonacci(n-1)+fibonacci(n-2)

print(fibonacci(2))